1. Field of the Invention
This invention relates to a rotor for fluidic apparatus such as blowers, compressors, fluidic actuation motors, vacuum pumps and the like.
2. Description of the Prior art
In a conventional rotor for the fluidic apparatus, the rotor comprises a drive shaft and a rotatable member rotatably mounted on the drive shaft.
A key and a keyway are used for connection between the drive shaft and the rotatable member.
In case of the key and keyway structure, it is difficult to avoid a clearance in the direction of rotation between the drive shaft and the rotatable member. Therefore, some play is apt to occur in the direction of rotation between the drive shaft and the rotatable member when the rotor rotates circumferentially.
To maintain compressibility efficiency as high as possible in the above mentioned fluidic apparatus such as a pump comprising a housing and the rotors held rotatably within the housing, it is necessary to minimize substantially the clearance between the two rotatable members of the rotors and also between the rotatable members and an inner wall of a housing in which the rotors are accomodated. However, in the case of the conventional pump where some play is necessary in the direction of rotation of the rotatable members, it is unavoidable to design the above clearance considerably larger than is required. This eventually fails in improving the efficiency in areas such as compressibility etc.
Japanese unexamined patent publication No. 63390/1984 discloses a structure in which each of a drive shaft and a rotatable member has a coaxially formed pin hole and a pin is pressed into both pin holes. In this known structure, however, the pin is apt to be deformed, although play in the direction of rotation of rotatable members may be prevented.